Recently, demand for high-resolution, high-quality video such as HD (High Definition) video and UHD (Ultra High Definition) video is increasing in various application fields. As video data has high-resolution, high-quality images, the amount of data is higher than for existing video data. Therefore, when the video data is transmitted using media such as existing wired and wireless broadband lines or is stored in existing storage media, transmission costs and storage costs increase. To solve these problems caused by the high-resolution and high-quality video data, high-efficiency video compression techniques may be used.
As video compression techniques, there are various techniques such as an inter-prediction technique for predicting the values of pixels included in a current picture from pictures that precede or follow the current picture, an intra-prediction technique for predicting the values of pixels in the current picture using information about the pixels included in the current picture, an entropy coding technique, in which the shortest code is assigned to the most frequently used value and the longest code is assigned to the least frequently used value, and the like. Video data may be effectively compressed using these video compression techniques, and may then be transmitted or stored.